1. Field of the Invention
This invention relates to a distance measuring apparatus for detecting the distance data of an object to be photographed, and in particular to a so-called active type distance measuring apparatus which emits an object distance detecting light from the photographing apparatus side toward the object to be photographed. More particularly, the present invention relates to a distance measuring apparatus using a plurality of light-emitting means and a plurality of light-receiving means.
2. Description of the Prior Art
A number of so-called active type distance measuring apparatus which apply a distance detecting light from the photographing apparatus side toward an object to be photographed have been proposed in U.S. Pat. No. 3,435,744 and others. These active type distance measuring apparatuses of the prior art are often designed such that a small spot light obtained by stopping down a light beam is projected to keep the accuracy with which the reflected light from the object to be photographed is received. Where such a spot light is used, if a plurality of objects to be photographed exist in the field of view, the spot light is applied to the position intermediate the objects with a result that the distance of a distant object in the background is detected and the picture-taking lens cannot be moved and controlled to a proper focusing position.
Further, in the apparatuses of the prior art, correct distance measurement has sometimes not been accomplished depending on the contrast or the like of the brightness of the surface of the object to be photographed.